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Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

GLACIERS OF HARRIMAN FIORD AND PORT WELLS
323
several hundred feet broad. The common boundary of the barren zone and forest was so well defined as to indicate that it represented a former limit of the ice, but there were no overturned trees. If the forest ever occupied the barren zone, and was there destroyed by an advance of the glacier, the occurrence was so long ago that the overturned tree trunks had disappeared through decay. The portions of the forest nearest the ice included no trees of large size, but as there were many standing dead trunks it is probable that the growth was mature and that the small size of the trees indicated merely conditions unfavorable to luxuriant growth. Translating these facts into terms of glacial history, it seems probable that the Barry had been, at sometime within the century, somewhat larger than when we saw it, but that it has not for a series of centuries exceeded the limit marked out by the neighboring forest. If any change had occurred within the last year or two it was of diminution.
"The opposite wall of the fiord is forested down to the water's edge, and it is thus shown that no recent advance of the glacier has carried it completely across the channel."
By 1905 Grant reports that "the extreme front of Barry Glacier . . . has retreated at least a mile* since 1899. The long front which projected into Doran Strait for nearly two miles has entirely disappeared, and the front is now .nearly straight across. The little tongue of ice which lay along the east side of the glacier has also disappeared." A photograph from Ft. Doran by Grant and Paige in 1905 (PI. CXXX, B) shows this retreat graphically in comparison with a photograph by Merriam; from nearly the same site, showing enormous changes both on the southwest and the southeast. Barry Glacier was revisited by Grant in 1908 and "its front was found to have retreated on the east
FIG. 44.   FRONT ov BABBY GIAOTBR.
Showing recession from 1899 to 1900 (After Grant and Higgins).
side about a fourth of a mile, and more than this on the west side."2 Grant's 1909 photographs (PI. CXXXI, A) show that a year later the retreat of the western edge had increased about 880 feet, and he has stated that the middle of the glacier had retreated half a mile. At this time Higgins made the map of Barry Glacier reproduced in Fig. 44, also showing graphically a decade of this retreat.
In July, 1910, the National Geographic Society's expedition found that the amount of retreat of Barry Glacier during the previous year was about 1600 feet on the eastern side and 500 feet on the western. There were disconnected ice masses above and in front of the glacier, in the area of fiord wall exposed by melting during that year.
At the terminus of the glacier in 1910, the vertical thinning by ablation during the S^ mile retreat from 1898 to 1910, amounted to 900 feet on the western and 1000 feet on the eastern side. Between the Cascade and Barry Glaciers, the ice surface was lowered 650 feet, and between Coxe and Barry Glaciers 700 feet. The curving medial moraines
» Given in a later publication as 1 Jt miles.
»About 2200 feet on the •western side, as measured on a photograph. Grant and Higgins state that the retreat in this period was four-tenths of a mile along the axis of the glacier.